However, did you know that Mount Everest is not technically the tallest mountain in the world? Everest is the highest point from sea level but, other mountains are larger. Mauna Kea, a volcano on Hawaii’s Big Island, is 4205m above sea level. This mountain rises from the ocean floor and its base to summit height is 10058m. This makes Mauna Kea the largest mountain in the world. It is also often thought that Everest is the closest Earthly point to outer space. However, as Earth is not perfect sphere and it bulges in the middle, the mountain with the closest point to outer space is Mount Chimborazo in Ecuador which stands at 6267m.